1. Field of the Invention
This application is directed to oligomeric/polymeric multifunctional additives prepared by reacting a suitable anhydride with (1) an aminodiol, (2) a diaminodiol or (3) an amidodiol, said diols containing at least one long-chain hydrocarbyl group (C.sub.12 +) thereby obtaining additive products highly useful for improving the low-temperature properties of distillate fuels and to fuel compositions containing same.
2. Description of Related Art
Traditionally, the low-temperature properties of distillate fuels have been improved by the addition of kerosene, sometimes in very large amounts (5-70 wt %). The kerosene dilutes the wax in the fuel, i.e., lowers the overall weight fraction of wax, and thereby lowers the cloud point, filterability temperature, and pour point simultaneously. The additives of this invention effectively lower both the cloud point and CFPP (Cold Filter Plugging Point) of distillate fuel without any appreciable dilution of the wax component of the fuel.
Other additives known in the art have been used in lieu of kerosene to improve the low-temperature properties of distillate fuels. Many such additives are polyolefin materials with pendent fatty hydrocarbon groups. These additives are limited in their range of activity; however, most improve fuel properties by lowering the pour point and/or filterability temperature. These same additives have little or no effect on the cloud point of the fuel. The additives of this invention effectively lower distillate fuel cloud point, and thus provide improved low-temperature fuel properties, and offer a unique and useful advantage over known distillate fuel additives. No art is known to applicants which teaches or suggests the additive products and compositions of this invention.